Sodium Ion Indicator in Zebrafish Embryonic Systems

Ions play an important role in cell signaling. There are many different types of ions including calcium, chloride, potassium, and sodium. Sodium, in particular, plays an important role in transmitting signals between neurons and maintaining an electrolyte balance. Imbalances in sodium ions can result in several diseases, such as epilepsy and heart failure Cells must maintain an equilibrium of ions inside and outside the cell. The unequal distribution of ions across the membrane results in a polarization and this is known as the membrane potential. In a neuron, upon being stimulated by some stimuli, ion channels located along the cell membrane will open, allowing an influx of sodium ions into the neuron, causing depolarization. This is then followed by the opening of potassium ion channels which allows an outflow of potassium ions, in a process known as repolarization. This process is known as an action potential and serves as an electrical signal between neurons. Currently, visualizing sodium concentrations has been limited to cell culture. The goal of this study was to identify a method in which we could visualize the distribution of sodium ions in live organisms in vivo. We designed an experiment in which we stained 3-day and 5-day zebrafish embryos with CoroNaTM green dye, which is a sodium indicator that emits green fluorescence at 488 nm when it binds to sodium. Utilizing the confocal microscope, embryos were visualized, imaged and analyzed for dynamic sodium ion distribution in tissues. We hypothesized that sodium ions will be dynamically distributed in different neuronal pathways and other tissues. Our experiments have revealed the dynamic distribution of sodium ions in the Olfactory neural pathway, cranial blood plasma and vessels, mitochondria rich Ionocytes over the yolk etc. More importantly, sodium ions are leaked upon injury and could potentially be an important cell communication signal for inflammation